This retrospective project is being conducted to further our understanding of the relationship between cigarette smoking and cocaine use. Our group has shown that there is a relationship between cocaine use and cigarette smoking such that cocaine abusers who smoke cigarettes use cocaine more frequently and in greater amounts than nonsmokers. We have also produced experimental evidence that cocaine use increases the rate of cigarette smoking. In addition, we recently reported that cocaine-dependent cigarette smokers report smoking more when under the influence of cocaine than when sober. In light of these findings, we will attempt to objectively document the self-reported increases in cigarette smoking associated with cocaine use in our cocaine-dependent clients. Towards this end, we wish to make use of data and urine samples we have collected at our cocaine-dependence treatment clinic over the past few years. The samples were analyzed for cotinine levels in the GCRC Biochemistry Core Laboratory. Results confimed patient self-reports that they smoke more when using cocaine. These observations combined with experimental results from our lab study provide compelling evidence that cocaine use increases cigarette smoking. Results were recently accepeted for publication.